1. Field of the Invention
The present invention relates to a gun arm apparatus primarily for use with a portable type resistance welding gun.
2. Description of the Prior Art
One type of prior art gun arm apparatus for a portable resistance welding gun comprises a gun arm main body having at its front end portion an electrode holder and at its rear end portion, a supporting member. A conductor connects the electrode holder to a secondary conductor terminal provided at the rear of the arm. A water passage means is provided for cooling the arm.
Additionally, there has been known with this type apparatus an arrangement such as that shown in Japanese Utility Model Application Publication No. Sho 57-24455. In this apparatus, the main body is formed of a tubular body made of a plate member of comparatively small thickness, and the conductor is formed of copper pipe, which is provided in the main body, and is also used for the water passage means. This arrangement, however, is inconvenient in that it is difficult to provide sufficient strength to the main body and it is difficult to make the conductor with a sufficient electric current capacity.